


The Fighting and Most Sensible Brothers Black

by Haunted_Frost



Category: Harry Potter - J. K. Rowling
Genre: Animagus, Book 5: Harry Potter and the Order of the Phoenix, Brotherly Love, Gen, Grimmauld Place, Marauders' Era, Regulus Black Lives, Sirius Black Lives
Language: English
Status: Completed
Published: 2017-06-22
Updated: 2017-06-22
Packaged: 2018-11-17 12:12:05
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,173
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11275089
Author URL: https://archiveofourown.org/users/Haunted_Frost/pseuds/Haunted_Frost
Summary: Snippets of Sirius and Regulus growing up, growing apart, and growing together again.





	The Fighting and Most Sensible Brothers Black

**Author's Note:**

> I'm totally going to edit/expand this, as I wrote it within a few consecutive hours, and there needs to be more. I plan to add a little angst, a little fluff, a little more of a reunion scene, and maybe a continuation of the ending through the rest of the books.

**Everyone knows that if you’ve got a brother, you’re going to fight. – Liam Gallagher**

They wrestled through childhood, battering one another in the grass, tugging, pulling on hair. They played like two little siblings often do—without a care for dirt or rocks or grass. Without consequences, because they were too little to do real damage.  Though Sirius was warned, repeatedly, that his little brother was smaller, that he had to be careful. He always was. He always protected Regulus, let his younger brother yank at his shaggy hair but only lightly tugged back.  They were brothers, glaring at one another over the dinner table while their father shouted about ruining their good robes that they were meant to wear to their cousins’ dinner party.

“Sirius started it,” Regulus lied, and Sirius shrugged. Because Regulus was his little brother, and he could take it.

* * *

“Sirius was sorted into Gryffindor,” grumbled Orion, like they all hadn't really expected it. Regulus stared, wide-eyed, at the letter his brother had sent them all.

"Sirius is brave," he said with all the conviction a nine-year-old can muster, and neither Walburga nor Orion had anything to say to it when the adoring little brother said it as if Sirius were indeed an accomplished hero.

"Loads of blood traitors in that house," was all Regulus's mother said, displeased.

* * *

Sirius came back with sensibilities that outraged his parents.

"And Lily Evans-she earned top marks for our year like nothing, she beat the Ravenclaws!"

"Evans? Never heard of that family," said their mother.

"You wouldn't have; she's a muggleborn." Instant fire lit Walburga Black's eyes.

"Gone blood traitor, have you then?" she screeched, "Disgrace upon our house, honestly! How dare you praise a mudblood," she cursed, and Sirius's eyes lit up in response.

"She's a good person; doesn't that count for anything? Does someone have to be born in one of five Wizard families to satisfy you?" And Regulus was shocked, because all he'd ever known as an answer to that question was yes.  But Sirius had changed, now that he was at Hogwarts.

He said how no, blood status didn't make people good or bad or better. It was just the person themselves. He said how he was friends with a Potter and two half-bloods, how names didn't make the person.

How could Sirius abandon all they'd known in just a short couple of months?

So Regulus argued.

He argued that they were of the Most Noble and Ancient House of Black, that it was a bloodline of prestige. He argued that muggle blood couldn't possibly make magic strong enough to make a better witch than any pureblood. He argued, but with a sort of futility that he didn't quite believe, because what Sirius said made sense, and Regulus was a sensible person.

Still, they argued, though they never came to blows over it.

* * *

Regulus was quiet at Hogwarts, a Slytherin to make his parents proud. At the Sorting, Sirius had clapped louder than the Slytherin table combined, howling loudly but without words. Regulus was glad; he didn't think it would be appreciated to hear "That's my brother!" in an opposing house.

Sirius was of the same mind, but it didn't matter, because Reg was in Slytherin, and that kept him safe from their parents' wrath.  Sirius loved his brother.  He wasn't stupid enough to make him a target.  

Perhaps it was the latent echo of  _take care of him, Sirius, he's smaller than you_ that stayed his tongue, that made him soft when in all other circumstances he'd be sharp.  Perhaps that's what stopped the fight in him, when Regulus turned his nose and went to the house clad in green.  

Regulus came to hear of the Marauders, a group of mystery pranksters that signed their work at every turn as such. They were good enough at what they did to target all of the houses, but it was clear they had it out for Slytherin with the more nasty pranks.

Reg knew it was Sirius and crew, because the Slytherin-directed pranks almost always wore off on him first.

The retaliation was always just as unkind, and when the whole of Gryffindor turned lime green for a week, Regulus made sure it stayed in Sirius's hair for another three days.

When they were young, they were like the same person--curious, fun-loving, all of that. They'd loved mythology, the stories behind their first names. They'd loved playing together.

They were Blacks, both of them, proud and fierce.  Cousins to Narcissa and Andromeda and Bellatrix, they were born to be legends themselves.  They were cut from the same cloth, Sirius every bit as ruthless as Bella defending his younger sibling from harm.  They were children, and they were brothers, and they were the same.   

But now Sirius was a Gryffindor, and Regulus was a Slytherin.

Sirius was brash, loud, flirting with girls and with danger all at once. What once was poised, groomed fierceness became blatant, outlandish chivalry.  Regulus was quiet, calculating, hungry for knowledge. He just wanted to know things, which, as the Sorting Hat said, nearly made him a Ravenclaw, except that he was determined to make sense of the world, rather than simply open to possibilities. Sirius no longer measured risks like a noble, like they'd been taught to--he simply shouldered his way to the front of the crowd, pushing until he was in the spotlight.

Now Sirius was a Gryffindor, and Regulus was a Slytherin.

* * *

Sirius came over for holidays once with Regulus, which went about as well as was expected. Sirius's bedroom was bright red and gold, filling slowly with Muggle band posters.

"At least with all the red it sort of looks like we decorated for Christmas," Regulus commented, and Sirius barked a laugh.

"I guess so."

But Mum had screeched over it, had blasted at the posters only to find strong sticking charms, had called Sirius a traitor, and Regulus didn't fight because it wouldn't do any good.

Sirius did.

He shouted back obscene things, called Mum and Dad both bigots. Voices raised higher and higher until Regulus stood up swiftly, retreated to his bedroom, and slammed the door. The Silencing Charm helped, if only a little.

"Merry Christmas Eve," he muttered towards the mirror he shared with Sirius once he was ready to fall asleep.

"Merry Christmas Eve," he heard his brother reply with a yawn.

Regulus got Sirius a copy of his book on advanced Transfiguration and Animagi, because "you annoy your head of house so much I imagine you forget what goes on in her classes".

Sirius got Regulus a practice Snitch, because he was planning on "losing at Quidditch for the rest of your Hogwwarts carreer, and you might as well give a valiant effort". Sirius got new dress robes, and Regulus got his own owl (they'd shared theirs up to that point).

"Be careful Reggie, or I'll start sending you annonymus letters," he joked as they packed for school again.

"You, or the Marauders?" Regulus replied smugly. Sirius gaped for a moment.

"I was that obvious?"

"Why do you think your hair was still green?"

"You little git!" but it was said with no malice, and Sirius was smiling. So he still had a brother.

* * *

According to records, Regulus no longer had a brother.

It was his fourth year. Sirius would still have his own Gringotts vault, and his last name would be Black, but he wasn't the Heir, and he wasn't on their family tree, and he wasn't allowed home except to collect his things.

"I'd almost be glad," he admitted, "Except I'm leaving you with them."

"They're not awful to me, Sirius."

"That's because you've always been the favorite," Sirius smiled ruefully, "My favorite, too. Don't fall in with the wrong crowd, though, Reggie."

"It's Regulus."

"Yes, well, just . . . Snivellus and his gang. Goyle, all them. Be careful. I'm pretty sure they're going to join You Know Who in the war that's coming."

"Is it really such a bad thing to want a little more order in our world, though?" Regulus complained, "The Ministry is so messy. You know that." Sirius paled.

"He's killing muggles. For sport."

"You don't know that--maybe they've done terrible things," Regulus argued, "Maybe muggles aren't all adorable little ignorant people. Maybe some are dangerous. You know that.  Look at the wars they've already caused."

"I don't think he's some kind of vigilante, Reg. I think this is bad news," Sirius warned.

"I'll be careful."

* * *

Sirius saw the Dark Mark on his arm and stumbled backwards.

"I thought you said you'd be careful."

"I'm not doing any killing, Sirius," Regulus said, and though his brother believed him . . .

"Doesn't mean you're not participating."

"I'm not. I'm doing what's right, Siri. I'm--" he gulped a breath "--I'm not with them. I'm trying to take them down from the inside, Sirius, you've got to understand."

"Reg," Sirius said, voice straining, "You can't do it alone."

"I've got to, or they'll suspect me. I've got to immerse myself with them, pretend to be a part of it. I've got to, Sirius, or innocent people--god, you were right, it's innocents--are going to be massacred left and right. I know you're in the Order of the Phoenix."

"You what?!"

"There's a spy. I don't know who; the Dark Lord just announces that his servant has been spying on you all. Just--get this to Dumbledore, okay? He needs to know how to beat him. It's nearly impossible without this information, got it?"

"I--yes."

"And I probably won't see you again, Siri, unless he dies soon." And Regulus's face was so grim, that Sirius shook his head.

"No. No, you aren't going to die, Reg, you can't do this to me. You can't leave me alone."

"You'll have James and the others," Regulus shrugged, "They're more your family than I am, now."

"That's not true. You're my brother, Reg."

"Sirius, when is the last time you and I spoke?"

"Doesn't matter." Regulus shook his head.

"Here. Take the other mirror. I can't get caught with it." With a crack, Regulus was gone.

* * *

And dead. Regulus was dead. He felt the burning water in his lungs when something, someone, pulled him out.

Kreacher. The little elf nearly killed himself with a beating for disobeying, but Regulus told him to stop.

Apparently it would take a little more than house-elf magic to destroy the damn thing. So he took it with him and hid it in Number 12, because that would be the best place for something so dark.

"Keep your distance from it, but make sure it stays protected," Regulus warned, "I'll find a way to destroy it and I'll even let you do the honors, I promise."

So Regulus looked around Number 12 for his old Transfiguration book. Within a year, he was able to turn into a long-haired black cat at will, and withdrew all of his money at Gringotts as the cat only to put it in Sirius's vault, making him the heir again.

He kept tabs on things, searched for more horcruxes, but didn't have very much luck. It was only after Halloween, after everything, that he stopped.

No, Sirius would never have betrayed the Potters. But with no trial, with no one to take the blame-and with the explosion in public, well, Sirius was in Azkaban, and Regulus, who belonged there for even studying terrible dark magic, was free. His brother, who'd been better to him than he could imagine, who'd taken care of him even on the opposing side, who'd taken all the heat from their parents . . . well, with Dementors sucking his happiness from him every moment, Sirius would not be the man Regulus remembered for long.  That left no one for Regulus to care about, to save.

So he ordered Kreacher to take care of things, and remained a cat.

The animal mind, when he embraced it, dulled the hurt just a little. It was easier to lose oneself in instinct.

He lived that way for fourteen years. And then Sirius showed up at Grimmauld Place, scowling as much as he had over his last time there, packing everything for the Potters'.

"Kreacher, you adopted a cat?" Sirius asked when he saw Regulus, who was frozen in place. The elf paused, glancing at Regulus.

"Master Regulus left it with Kreacher before he tried to defeat the Dark Lord, he did." Thank goodness for Kreacher's dislike of Sirius. 

Sirius's face softened a margin.

"Well, I'm back, so I'm your master, Kreacher."

"Mistress would be displeased."

"Well, Mum, Dad, and Reg are all dead, so you're stuck with me," his brother sneered (he'd never tell him, but it was just like cousin Bella's).

* * *

So the Order of the Phoenix moved into his house, and he became a sort of pet.

"Moony!" Sirius called, and Remus came.

"What is it, Padfoot?"

"What should we name the cat? Reg left it with Kreacher when it was a baby, likely."

"Well, it's a black cat to your black dog. Padfoot Jr?"

Regulus hissed. He wasn't going to be Jr anything.

"Nope. But it's not far off from something. Hm. He's like a little lion, with all the fluff around his neck," Sirius chuckled.

"Call him Simba, then," suggested Hermione, who was making dinner, "It's Lion in Swahili. I watched that adorable Disney movie, the Lion King, and that's the main character. It's actually based off of Hamlet, but it's really wonderful."

"Simba. You okay with that, hm?" Sirius scratched Regulus behind the ears, and that felt good. Besides, he chuckled inwardly, Regulus was the Heart of the Lion in the sky, after all.

* * *

"You're what?" asked one of the red-haired twins that reminded Regulus so much of their late uncles.

"I'm Padfoot, and this is Moony. We're one-half of the Marauders."

"Oh, so Moony--that's because you're a werewolf, yeah," one said, and Regulus blinked. Quiet, sickly Remus Lupin? A werewolf?

"And the rest of us became unregistered Animagi," Sirius continued, and what. "Wouldn't have been able to do it without an advanced Transfiguration book I got for Christmas. As animals, we could help Moony stay calm and keep him from being lonely without anyone getting hurt."  Stupid, brave Sirius.   

"So, Wormtail and Prongs?"

"Wormtail is Peter Pettigrew. He was a rat--your pet rat for some time--who betrayed us all and framed me." The twins paused before asking who Prongs was.

"It's for his antlers; he was a stag--James Potter. I was very surprised that Harry managed to get the map, but with you two involved I suppose it makes more sense," Remus smiled.

Regulus left to annoy Molly, who'd taken a random dislike to Sirius.

* * *

He overheard Sirius talking to Harry about him. About the family tree. Regulus meowed and sat on the arm of the chair Sirius had settled in.

He stayed with Sirius, convinced Kreacher in secret to take care of his brother. Sirius seemed surprised to find Kreacher being nice, but was nice in kind, so the elf warmed up to him.

They still had issues with the portrait of mother, but little could be done when she'd taken a page out of Sirius's book and applied permanent Sticking Charms.

He dug up his old research and dropped it in an Order meeting. He comforted Molly when she dealt with the Boggart. He spent time with everyone in the house, whenever they were there. No one expected a cat to care about an Order meeting.

He mused that they were really careless about that one--after all, Sirius was proof that any animal wasn't what it seemed. But apparently he'd been sufficiently cat-like enough to fool them.  If he ever turned human, he doubted they would trust him easily.  He was so catlike, apparently, that Ron offered to take him to Hogwarts so Sirius wouldn't have to take care of him--but Remus refused.

"Sirius needs all the companionship he can get," Remus muttered, and that was the truth. He'd seen his brother's eyes, coming in, still haunted from Azkaban. No amount of chocolate would bring him back whole, though time improved his demeanor somewhat.

The Horcrux research worked. Soon, they were discussing possible items and locations of each, and how to destroy them, in addition to their talk about the prophecy. Regulus knew--he'd heard Severus plead to the Dark Lord to spare Lily Potter. Regulus had known from that moment that the Potters were doomed. So the prophecy wasn't news, but its content was. 

* * *

It was spring, and a fight had broken out at the Department of Mysteries. Regulus knew, a horrid feeling in his gut, that this would not end well. He transformed back for the first time in over a decade, grabbed one of Sirius's cloaks, and Apparated into the Ministry.

Death Eaters and Order Members and children fought. He hexed Amycus and Alecto both on the way through to the one room he knew he'd find them in. The Veil was, after all, dramatic, and the Dark Lord had a flair for dramatics.

There was Bellatrix, duelling Sirius much too close to the Veil. She sent a stunner and all Regulus could do was run, barreling into his brother, the spell hitting the dais instead.

"Move, Harry," Regulus called, "We'll handle dear cousin Bella. Get out of here."

The boy scrambled, glancing once at Regulus's face before hurrying away.

"Regulus?" Sirius asked, breathless.

"Talk later, Getting away from the deadly curtains now," Regulus snapped, deflecting another spell from their cousin.

"Reggie?" she asked with a sugar-sweet smile.

"Turns out us Blacks are particularly well-versed in hiding out, eh, Sirius? Protego! Stupefy!"

"Confundus! Where exactly have you been hiding, then?"

"Well, I wouldn't have chosen the name Simba, but I suppose it's fitting."

"You absolute tosser."

"Great minds think alike. Couldn't exactly walk into an Order meeting, undead with a Dark Mark on my arm. That's it--Sectumsempra!" he finally cursed, and Bellatrix was too slow to react. She screeched as it hit her point-blank, and she ran to her master.

"Good to be out fighting again, eh?" grinned Regulus in spite of himself as they gave chase.

"As long as we're fighting together," Sirius nodded back. They hurried on.

* * *

Everyone miraculously survived the fight at the Ministry, and Sirius was cleared of all crimes, and Regulus was declared not-dead. Overall, a victory.

Even when Harry came to live with them. Because Remus and Sirius had suddenly adopted the boy, and Regulus wasn't exactly going to move out.

"I'll be the long-lost Slytherin uncle," shrugged Regulus, "While you three play house. It's a good thing the Ministry looked at our memories this time round."

"So you were Simba?" Harry exclaimed, "You're literally a cat version of Padfoot; I'm not kidding."

"He's not wrong," shrugged Remus with a grin, "No one would have expected it.  You're more alike than meets the eye."

"No," Regulus shook his head, "I think it makes perfect sense."


End file.
